It depends on what you define as primary interface. The primary interface is really the USB connector, since combox can work with many flash drives, music players, and handsets for music playback.

Combox control unit is the electronics and software that allows iDrive to work with external sources for music (and video). It supports three wired inputs. One via the USB interface, one via the cradle, and then the regular aux jack. On other vehicles it can support additional USB interfaces that may be located in the rear of the car.

It also supports all the bluetooth functionality ... including telephone BT and audio BT streaming. It handles the cataloging of music files, album art, etc. Newer versions support the BMW apps platform and BMW live and BMW internet.

Additionally, Combox can be purchased with telematics, for BMW assist services too.

Thanks for the clarification on the location, though I remember someone sayin early comboxes were under the front passengers seat ehh.

I'm confused one aspect. If analog audio is supported, but not video or iPod out, how will the apps platform work on the car?

Why does this matter?
CAUSE EVERY TIME someone says Lexus has better build quality, one should consider what Toyota their Lexus Engine and chassis platform comes out of and how long that part has been tested in the real world!